Container opener



8- 1964 J. A. YERKES 3,143,904

- CONTAINER OPENER Filed Feb. 27. 1961 8 Sheets-Sheet l Ill- 112 INVENTOR JJOHN'A.YERKES I BY WW viz m ATTORNE .5

Aug. 11, 1964 J. A. YERKES 3,143,904

CONTAINER OPENER Filed Feb. 27, 1961 a Sheets-Sheet 2 INVENTOR J OHN A.YERKES BY Fmw ATTORN S 11, 1954 J. A. YERKES 3,143,904

CONTAINER OPENER Filed Feb. 27, 1961 8 Sheets-Sheet 3 OPENER IN 5 9 PLACE ON CAP V OPENER SWUNG T0 TURN CAP I INCORRECT POSITIONING OF TEETH Tic] IO SHOWING EFFECT OF SWINGING OPENER SHOWING EFFECT OF SWINGING OPENER OF FIG."

INVENTOR JOHN A. Y ERKES BY 7 6652 U2 ATTORNE S 0 OPENER WITH TEETH INCORRECTLY ORIENTED Au 11, 1964 J. A. YERKES 3,143,904

CONTAINER OPENER Filed Feb. 27, 1961 8 Sheets-Sheet 4 ly ziillll-lwz 4 gip glllnmiz 7 INVENTOR JOHN A.YER KES BY WWW ZZZ ATTO R N EY Aug. 11, 1964 J. 'A. YERKES 3,143,904

I CONTAINER OPENER Filed Feb. 27, 1961 8 Sheets-Sheet 5 a l 4 92 HF 'i 25 m 1 IEF i122 INVENTOR JOHN A.YERKES ATTORNEYS Aug.- 11, 1964 J. A. YERKES 3,

CONTAINER OPENER Filed Feb. 27, 1961 8 Sheets-Sheet 6 T ITZB a I m 30 L fr" INVENTOR JOHN A- Y ERKES Fauna- 4 m ATTO R N EYE:

U nit d. S es Pa en 3,143,904 CONTAINER OPENER John A. Yerkes, New York, N.Y.; Gulda Morrison Yerkes, executrix of John A. Yerkes, deceased, assignor to Gulda Morrison Yerkes Filed Feb. 27, 1961, Ser. No. 32,010 Claims. (Cl. 813.4)

This invention relates to a device for operating upon container closures, and particularly to means for detaching screw caps, crown caps, tumbler caps and the like from bottles, jars and cans, as well as for lifting can lids and other friction-type closures and for piercing beverage cans.

Prior devices have not been satisfactory, as will appear hereafter, because of various reasons set forth herein. No attempt will here be made to dwell on the details of the many defects which may be found in the prior art. For example, in devices for unscrewing tight screw cap s, the production of dangerous burrs is common in the art, as is seizure of the loosened caps, due to wedging between the jaws and often requiring the aid of a pry tool to loosen them. Common also is inadequate gripping by the jaws with resulting annoying slippage and frequent complete failure to unscrew the caps as well as producing sharp burrs. Also common in the art is the requirement for high crotch pressure; that is, a strong force must be exerted against the cap and directed toward the smaller end of the crotch, in an attempt to make a slipping device take hold, a highly unsatisfactory procedure as will be explained later herein.

Investigation of the causes underlying the defects of the devices of the prior art revealed an amazing variety of contradictory specifications involving vital elements, and there was ample evidence that even the most essential principles were generally either unknown or were completely disregarded.

One of the objects of the invention is to enable easy removal of screw caps which are tightly secured to their containers, embracing a large range of sizes of caps, with the requirement of little effort and no special skill or. knowledge and, in addition, requiring the use of a negligibly small force to urge the cap relatively toward the apex of the crotch.

Another object of the invention is to effect removal of screw caps without injury to the user and without damage to the cap, container or contents thereof, and which will not produce sharp, dangerous burrs on the cap when manually operated.

A still further object of the invention is to prevent improper use of the device by not permitting tightening of the cap when loosening is required, and by causing harmless slippage of the gripping jaws when the device is turned in the wrong direction.

A still further object is to provide a device in which caps which have been unscrewed from their containers will not be seized and held by the jaws.

Another object is to provide a device in which the teeth of the trailing jaw have characteristics of form, pitch, orientation, relative height and location with respect to other elements of the device, so that burrs, seizures and slippage are avoided.

A still further object is to provide a device in which the angle of crotch is selected to avoid the production of dangerous burrs, seizure of the caps, slippage and failure to unscrew tight caps, and to avoid the need for high crotchward pressure on the caps.

A still further object is to provide a device which is portable so that it may be carried to the container.

wherever it may be, and so that it may be tilted if convenient or to help avoid spillage, but which may alternatively be rigidly secured.

A still further object is to provide a combination opener in which the relatively long sides and extension handle of the screw cap opener comprise an unusally long handle' for the other opening devices, with great convenience and of such substantial leverage as to make operation of the other devices unusually easy.

In one aspect of the invention, the device may include a body member having a pair of jaws arranged to form a crotch, the angle between the jaws, as will appear hereafter, being between 33 and 38 degrees. One of the jaws is a leading jaw and the other a trailing jaw, the leading jaw having a smooth surface and the trailing jaw hacing teeth thereon for gripping screw caps. The teeth preferably are file-like, inclined toward the narrow end of the crotch, and have a pitch between 33 and 47 teeth per inch. There is a flat portion on the body member between the jaws to provide a flat abutment surface for screw caps gripped thereby. In one form, the effective height of the cap-gripping elements of the jaws isbetween V and 7 of an inch. The planes of the gripping surfaces of both jaws are disposed substantially at right angles to' the aforementioned abutment surface.

In a further aspect, the bridge between the jaws has a multiplicity of ports so that any screw caps engaged thereby can be seen therethrough and still maintain strength. The body member may have a handle extension integrally formed therewith, extending a substantial distance beyond the abutment surface. The teeth means may be formed integrally with its jaw or may be arranged to be fastened thereto.

In addition to the other aspects, the body may have a crown cap lifting member, a pair of hooks for engaging under and lifting friction caps, a piercing member, and a pry member for lifting can lids and frictionally held bottle caps and the like in which the pry member reacts against a bead or shoulder. As will appear hereafter, the combination and various aspects of the invention provide a means for detaching screw caps, crown caps, tumbler caps and the like in a more efficacious manner than is found in the prior art. i

The above, other objects and novel features of the invention will become apparent from the following specification and accompanying drawings which are merely exemplary.

In the drawings:

FIG. 1 is a plan view of a simple form of screw cap turning device showing also an optional provision for an opener of crown-type caps;

FIG 2 is a sectional view taken along the line IIII of FIG. 1;

FIG. 3 is a central section taken along the line III-HI of FIG. 1;

FIG. 4 is a plan view of another form of screw cap opener combined with means for opening other types of closures;

FIG. 5 is a broken enlarged view adjacent one of the apertures of FIG. 4;

FIG. 6 is a side view of FIG. 4 with a small partial cutaway section showing a toothed insert;

FIG. 7 is a schematic view of a pair of connected jaws,:

one of which is toothed, the teeth being greatly enlarged for clarity;

FIG. 8 shows the device of FIG. 7 after the initial or FIGS. 14, 15 and 16 are similar to BIG. 13 except that there are certain modifications to the jaws;

Patented Aug 11, 1964 FIG. 17 is an alternative form which differs from FIG. 13 in that the jaws are spaced, as often shown in the prior art, with gaps above the jaws;

FIGS. 18 through 25 are fragmentary views which illustrate the operation of the many combined opening devices of FIG. 4, showing the initial positions just prior to opening operation;

FIGS. 26 through 31 show fragmentary views which illustrate some of the various types of caps which may be unscrewed by the present invention; and

FIGS. 32 through 43 are graphs of a large number of experiments and tests made under varying conditions and illustrating the superiority of the present invention.

In order to facilitate a clear understanding of the underlying principles of the present invention and to define certain terms, reference is made to schematic drawing, FIG. 7. A screw cap opening device 1 is shaped generally in the form of a blunted V or crotch. One leg of the V is designated the leading jaw 2 and has a smooth gripping surface 3 on its inner edge. The other leg is designated the trailing jaw 4 and its inner edge is provided with teeth. Since the characteristics, location, etc., of these teeth are part of the essence of the present invention, they will be described in detail at this point.

T th Characteristics, Location, Orientation, Etc.

(See also section headed Pitch of Teeth) The teeth are of the form generally described as cutting teeth and may be found, with variations, on files, milling cutters, saws and the like. As will be shown later, it is essential that these teeth be made quite sharp. Any rounding, flattening or other blunting of the cutting edges will result in inferior operation. They should be hardened and made of a good grade of steel or equivalent.

As shown in the schematic drawing of FIG. 7, the teeth have relatively short, steep faces 6 which are oriented so that they face toward the apex D of the crotch, such orientation being of particular importance in the present invention. A slight negative rake on faces 6 has been found advantageous in experiments made on the present invention. The back portions of the teeth, gently sloping surfaces 7, are shown as straight lines in the drawing, but preferably they are comprised of a pair of lines joined together as in typical file-tooth construction. An excellent example of the preferred fine-pitched file tooth may be seen on the narrow edges of a 12-inch size so-called flat smooth file of the well known Johnson brand file. Preferably, as on that files edges, the teeth are cut vertically across the edges, but it is within the scope of the present invention to use teeth which are cut on a bias.

Teeth, such as described above, have directional characteristics, essential to the present invention, in that they tend to engage, bite into and cut when relative movement is in the proper direction, and to slip harmlessly when relative movement is in the opposite direction, especially harmlessly if the pressure against the teeth islight. As employed in the present invention, the teeth are required to engage and bite into the metal of the screw cap, but cutting, in the sense of metal removal, is neither encouraged nor permitted.

A further essential requirement in the present invention is that the teeth be located on trailing jaw 4 alone, and that the gripping surface of the leading jaw 3 be smooth and without teeth.

The pitch of the teeth preferably should be 38 teeth per inch or within a preferred range, for reasons which are fully discussed in the section headed Pitch of Teeth. For purposes of clarity, the teeth in FIG. 7 are shown greatly enlarged.

In a preferred form of the device which will be described lated, the teeth are formed on a separate strip which is attached to the trailing jaw.

' Continuing with the description of schematic FIG. 7, the included angle of the crotch is preferably 35 or within a preferred range, as will be fully explained in the section headed Angle of Crotch, where it will be shown why it is of the essence of the invention thus to limit the crotch angle. FIG. 7 shows a top plan view with a screw cap 8 shown lightly engaged by both of the jaws 2 and 4. Contact is made tangentially at points A and B on cap 8, these points being the extremities of radial lines AC and BC. It should be understood that the pressure exerted against the cap to hold it against the jaws, hereinafter to be designated the crotch pressure, is extremely light; that is, the cap is urged into simultaneous engagement with both jaws with a very low force. The advantage of a low crotch pressure will be discussed in the section headed Crotch Pressure.

Operati0n-Schematic Form The operation of the simple schematic form shown in FIG. 7 will now be described so that an understanding of the principles involved may be obtained. Referring to FIG. 8, when the device is initially swung in a generally counterclockwise direction as shown by the arrow on arc G, the cap 8, which is assumed to be tightly secured to its container, does not commence to move immediately. The initial or gripping swing, exaggerated for purposes of clarity in FIG. 8, may be described as follows. In spite of the low crotch pressure mentioned above, the teeth instantly dig into the cap, the teeth being sharp and hard with the cutting faces oriented as required, and the screw caps being made of the usual relatively soft metals or plastics. The teeth do not disengage nor is there relative slipping or sliding of a tooth along the surface of the cap, in proper operation. Experiments made on the present invention show that the tighter the cap, the more firmly the teeth dig in and hold the cap. Observation has shown that during the initial swing, the termination of which is shown in FIG. 8, the cap remains fixed. Since the teeth refuse to slip, the device rocks around point A as a center, so that apex D swings approximately along arc G to D, with a radius R, as shown. With leading jaw 2 having a smooth surface with low friction, it will be clear that fixed cap 8 is now forced strongly toward apex D; that is, there is a strong force which tends to wedge cap 8 into the crotch. When the cap is extremely tight, the wedging becomes deeper and deeper as the initial gripping swing continues, and the teeth 5 dig in deeper and deeper and hold more tightly.

Upon completion of the initial or gripping swing, that is, when the seal is broken and the cap starts to turn, the secondary swing is merely a simple unscrewing action.

It is important to note that when caps are very tight, more and more teeth dig in and become effective, so that when the initial swing is completed, instead of a tangential contact as A as above described, there is chordal contact, as between points M and N in FIG. 8, such being shown exaggerated for clarity. At the leading jaw 2, on the other hand, there is relative sliding contact between cap 8 and the smooth surface 3, as the cap moves relatively into crotch, as described. With very tight caps, the cap is flattened as at chord E to F, greatly exaggerated in the drawing. Thus, with a pair of opposed chords as described, the grip becomes similar to that of a monkey wrench with teeth on one jaw, acting on the flat surfaces of a nut, resulting in the easy removal of extremely stubborn caps. As in the wrench mentioned, there is no need for crotchward pressure, the wedging action in the present invention occurring automatically when the device is swung as described. Selection of the proper angle of crotch is of the essence in obtaining the automatic wedging operation described above, for if this angle is either too large or too small, there may be failure to grip in the former case and overwedging in the latter case, as will be shown in the section headed Angle of Crotch.

It should be noted that if the device is turned in the wrong direction, that is, clockwise in FIG. 7, the user is instantly warned of his error by the harmless slipping with occurs.

It should also be noted that with the open construction shown schematically in FIG. 7, if the device is inverted, it will operate properly for tightening caps. The toothed jaw will still be the trailing jaw and the teeth orientation will still be correct, but no longer for loosening caps. In the description of the preferred embodiment of the invention, it will be seen that the open construction of FIG. 7 is not used, so as deliberately to defeat such inversion and assure against turning in the wrong direction.

To further demonstrate the essential nature of the preferred structural elements, comparisons will now be made with certain constructions commonly found in the art which fail to function satisfactorily.

Why Teeth Must Be Located on the Trailing Jaw Alone Referring to FIG. 9, a construction is seen which differs from that of FIG. 7 by wrong positioning of the teeth on the leading jaw, designated LI, and with the trailing jaw TI wrongly made smooth and toothless. The teeth are oriented so as to tend to engage the cap for unscrewing operation. Attention is directed to contact point P on the trailing jaw where it tangentially contacts the cap. Referring to FIG. 10, it will be seen that the teeth tend to hold the cap near point B, and the device rocks around point B swinging on a radius R, so that apex D swings to D' along arc G, as shown by the arrow. Instead of a tendency to wedge and grip as in the construction of FIGS. 7 and 8, there is a definite opposite tendency. Point P on the trailing jaw will be seen to have swung completely out of contact with the cap. Thus, instead of a tendency to wedge and grip tightly, there is a tendency to swing the trailing jaw out of contact with the cap. In experimental trials with such structures and tight caps, there was complete failure to loosen the caps, no matter how heavy the applied crotch pressure, and the slippage resulted in the production of sharp, dangerous burrs which were capable of inflicting severe cuts.

Why the Teeth Must Be Oriented Properly The importance of using directional teeth properly oriented is shown in FIGS. 11 and 12, the construction being identical to that of FIGS. 7 and 8, except that the teeth are wrongly oriented. In other words, the cutting faces of the teeth do not face toward the apex of the crotch. The consequences of such a defect will be apparent by inspection of the swinging action illustrated in FIG. 12. In spite of the heaviest applied crotch pressure, the teeth do not bite into the cap, and slide uselessly around the periphery thereof. There is notably no pivoting action of the teeth at point A as previously described relative to FIGS. 7 and 8; consequently, there can be no wedging action. Both jaws, therefore, rotate around the center C as illustrated, slipping uselessly. This action has been noted in experiments with other teeth of improper, nondirectional forms such as simple sharp V-shaped teeth, knurled teeth of both diamond and serrated shapes, square grooves and the like. Such teeth fail to engage and dig into the metal of the cap sufliciently for the required automatic wedging action described. These invariably fail to unscrew tight caps and, if sufficient crotch pressure is applied, the slippage conduces to the production of dangerous burrs.

General Construction Requirements A large number of tests were made using various types of jaws for the leading and trailing jaws. Many toothed forms were tested including cutting teeth, properly oriented; cutting teeth wrongly oriented; teeth blunted at their tips to varying extents; knurled, serrated teeth; simple, sharp non-directional V-shaped teeth like sharp threads; rounded teeth; dulled teeth, etc. All were tried on the trailing jaw or on the leading jaw or on both jaws simultaneously, in every possible combination. Where a blank, smooth jaw was used in the combinations, it was tried also with the surface roughened or broken to various degrees.

Not one'singl'e combination performed in an acceptable manner except the general combination of the presentinvention. In all of the other combinations, there was either failure by slippage or intolerable seizures or both, often accompanied by dangerous burrs, when tight caps were unscrewed, such being encountered with great frequency. Not only is it customary to seal containers tightly to insure long shelf life when the containers have volatile contents, but when many substances have been permitted to drip onto the threads of the cap or container, drying or hardening thereof will form a very tight seal.

Description of the Preferred Forms The following description will be confined to those elements of the preferred construction which pertain to the unscrewing of tight screw caps. Referring to FIGS. 1 through 6, a body portion 10, preferably die formed from sheet steel, is bent down to form a pair of sides. One of these is leading jaw 2 which has a smooth inside capgripping surface 3, the other side being designated as trailing jaw 4. It is within the scope of the present invention to use sides which are not integrally formed with body portion 10 but which may be separate pieces secured to the body portion. Secured to the inside surface 11 of trailing jaw 4 is a toothed strip 12, preferably held by means of rivets 13, but any other suitable fastening means such as screws, spot-welding or the like may be used. As shown in fragmentary FIG. 5, toothed strip 12 fits snugly against the inside surface 11 of trailing jaw 4. As shown in FIG. 2, the strip 12 is of such height as to terminate flush with the bottom of the trailing jaw 4. The identical height of the toothed trailing jaw and the smooth leading jaw is carefully chosen and limited to a narrow range, for reasons which will be explained in invention to provide for this valuable element of the construction by forming strip 12 with one or more bent lips for engagement in mating holes or depressions formed in the jaw 4, thus absorbing the thrust.

The jaws are disposed in angular relation to each other, forming a blunted V-shaped crotch having an in-. cluded angle of 35 or very close thereto. The importance of this choice of angle will be fully explained in the section headed Angle of Crotch.

The sides may be grasped on their exteriors for use as a handle. Near the lower end, the converging sides widen substantially, becoming parallel and greater in height to form an extension handle 15. This not only adds to the convenience of manipulation with smaller caps, but also contributes substantially to the ease of operation by increasing the available leverage. This is achieved with only insignificant addition to the cost of manufacture since the extension handle 15 is made on the same dies and with the same operations as the body portion 10. When extremely tight caps of larger jars are to be unscrewed, the additional leverage is highly desirable.

The use of a separately fabricated strip 12 is advantageous because of the greater practical latitude in the choice of materials, the method of cutting the teeth, the hardening and other practical reasons. It is within the scope of the present invention, however, to modify this element of construction. Reference is directed to FIGS. 13, 14, 15 and 16 which are partial sections of the type shown in FIG. 2. FIG. 13 shows a screw cap as it is engaged by toothed strip 12, on trailing jaw 4, and by smooth leading jaw 2. FIG. 14 shows teeth which are formed integrally on inner surface 11 of trailing jaw 4. Such teeth could be milled or broached on a raised pad on the metal blank before bending down the side, or they could be cut afterward by a reciprocating tool such as a gear shape'r. FIG. 15 shows that the smooth leading jaw surface 3 of leading jaw 2 may be provided with an inserted strip 17 which has been hardened. Such a construction would be of advantage where the body portion 10 is not hardened. FIG. 16 shows a toothed angular strip 18 having teeth 20 on its inner surface. In such a construction, it is convenient to secure strip 18 to abutment member 21 by means of rivets 19.

FIG. shows a greatly enlarged fragment of FIG. 4, clearly showing the required orientation of directional cutting teeth 5, with the cutting faces facing the apex of the crotch V. It must be emphasized that the teeth in FIG. 5 and in all the figures are shown substantially enlarged for clarity. Actually, the pitch of these teeth is preferably quite fine, and 38 teeth per inch or within a preferred range discussed later herein. The importance of using such unusually fine teeth will be discussed in the section headed Pitch of the Teeth. Other important characteristics of the teeth have already been treated in the section headed Tooth Characteristics, Etc.

Shown in FIGS. 1 and 4 are broken circles which indicate a range of large and small screw caps within the capacity of each of the figures. The larger screw caps 23 and 24 indicate the largest caps within the capacity of each, the small cap 25 being the same for each. A substantially smaller cap than that shown can be used, of course, within the capacity of both figures. It is also important to noted that the range of cap sizes is very large. To accommodate such a large range of sizes in an open-end construction of the type shown in schematic drawing, FIG. 7, would require extremely heavy and bulky construction to avoid springing apart of the jaws, or even permanent spreading. The prior art shows many such open-end constructions which are quite limited in capacity. In the present device, body portion consists largely of an abutment member 21 whose flat undersurface is designated as overhead abutment surface 26. When a screw cap is placed between the jaws and is moved inward toward simultaneous contact with both jaws, the correct gripping of the cap by the jaws is facilitated by keeping the top of the screw cap against overhead abutment surface 26, as the cap is being moved inwardly, the use of said abutment surface being quite important and conferring other advantages which. will be discussed fully in the section headed Overhead Abutment Surface.

As clearly shown in FIGS. 2, 6 and 13, both jaws are subtended from the abutment surface 26 with no gap whatsoever between the tops of the gripping surfaces of the jaws and the abutment surface. The prior art discloses many devices in which there are substantial gaps above the tops of the jaws, but such a construction is extremely detrimental to the operation, as evidenced by the results of many experiments and tests which will be fully discussed in the section headed Omission of Gaps.

Parts for Visibility As shown in FIGS, 1, 2 and 4 as well in greatly enlarged form in FIG. 5, the body portion 10 is provided with a multiplicity of ports or apertures 27 near the trailing jaw 4 and a like number near the leading jaw 2. It should be noted that there are unbroken metal bridges 23 between the ports, so that ample structural strength is provided to keep the jaws from springing apart or permanently spreading. Thus, a light and non-' 8 in FIG. 29 being especially diflicult to hold properly without good visibility near each jaw. Thus, one of the important aspects of this invention is to provide such good visibility without loss of structural strength.

Portability FIG. 1 shows a hole 29 suitable for hanging the device on a nail or hook, the preferred form being a device which is a portable hand implement that may be easily transported to any container which is to be opened, wherever it may be. While it is within the scope of the present invention to provide holes for screws or the like which would enable securing the device to a wall or shelf, convenience would be greatly reduced. Containers are often located at serving points remote from a fixed opener, with obvious inconvenience. Furthermore, users often prefer to hold the containers at an angle with the vertical when removing caps. In addition to these considerations, where the device is combined with other types of openers, as will be described later, a fixed device would entail awkard manipulation and danger of spillage.

Operation of the Preferred Forms The operation of removing screw caps from containers is similar in many respects to that already described in the section headed OperationSchematic Form, but there are important differences. The operation of engaging the screw cap simultaneously by both jaws and then turning the device to loosen the cap is similar, it being understood that the schematic form is equipped with the many preferred elements of construction previously specified, such as proper form of teeth with preferred pitch, orientation, location, etc., preferred angle of crotch; a smooth leading jaw surface and so forth.

Height of the Jaws The prior art shows a large variation in the heights of the jaws. Nearly all metal screw caps have a bottom curled ring 30 as shown in FIG. 13 and in many of the smaller fragmentary drawings. The diameter of ring 30 is substantially greater than the other portions of the cap, as shown in FIGS. 28, 29, 30 and others. The ring is structurally weak, there being substantial clearance between it and the container underneath. Tests made during the development of the present device showed that if the jaws reach and grip the ring, it readily collapses and unscrewing is made diflicult. Furthermore, burrs are readily produced, with consequent danger to the users hands. At the very least, the cap is badly distorted and often must be discarded. For this reason it was found that in the present invention the reach or height of the jaws should be limited so that with even the shortest caps which could be found, the bottom curled ring 30 not ben engaged by the jaws. Inspection of FIG. 30 shows that any substantial increase in the jaw height would enable it to reach and engage ring 30. The prior art shows many devices of the open-face type which, through lack of an abutment surface 26,- may inadvertently be caused to grip the bottom curled ring 30. Past experience has shown the futility of reliance on the skill and knowledge of the user to keep either abnormally high or open-face jaws from engaging the curled rings on the caps.

The prior art also shows many devices with jaws which are quite shallow in height, allegedly to assure that the jaws will engage only the upper cylindrical portion 31 of the screw caps. Unfortunately, devices with such short jaws cannot engage the cylindrical portion 31 of domed caps of the type shown in FIG. 29. The cap illustrated is accurately representative of many in actual use and many have higher domes. As will be seen, jaws having teeth 5 of such short height as to reach only the top cylindrical portion 31 of caps having the usual flat tops, will not reach far enough in many domed caps of the form shown.

In the present invention, it was ascertained that the construction should meet the requirement that the jaw height be short enough to preclude its reaching the bottom ring 30 on even the shortest caps in common use, yet be of sufficient effective height to reach the grippable cylindrical portion 31 of the caps in common use with the highest dome. Careful measurements of all obtainable caps showed that with relatively short lug type caps such as shown in FIG. 30, in the smaller sizes an effective jaw length of over about nine thirty-seconds of an inch would be unsafe. On the other hand, with hte higher domed caps of the type shown in FIG. 29, the distance from the top of the dome 32 to the grippable portion 31 is very close to three-sixteenths of an inch. Thus, in order to assure that suitable grip is obtained on cylindrical portion 31, the jaws must be at least three-sixteenths of an inch, but not longer than nine thirty-seconds of an inch, a practical range which allows for tolerances and normal variations. Consistent with these requirements, it is also clear that both jaws would stay within these limits and preferably both be of the same height.

In practice, the present device functions perfectly with all common types of caps, as shown in FIGS. 26 through 31. FIG. 26 shows a familiar type of tube with a small screw cap. It should be noted that the jaw height in no manner interferes with proper operation. FIG. 27 shows a similar tube having a cap with a hexagonal periphery 33. The device also performs perfectly with caps such as these, as well as with caps of the type shown in FIG. 31 which is a plastic cap often found on cosmetic ars.

In view of the definite requirements for close control of the height of the jaws, as shown above, the wide variations in jaw height in different devices and even between one jaw and the other in the same device, indicate widespread failure to recognize or solve the problems indicated.

Overhead Abutment Surface Overhead abutment surface 26 makes a valuable contribution to the construction of the present invention. It should be clear from the discussion in the section headed Height of the Jaws that without the use of the overhead abutment surface 26, control of the jaw height would be futile. The device would be as vulnerable to inadvertent gripping of the bottom curled ring 30 as any open-end type, as previously explained, even if the of preventing improper inversion of the jaws. It has pre viously been shown above that an open-end type of device, such as the schematic type shown in FIGS. 7 and 8, may be inverted, and the device will function correctly to tighten rather than loosen caps. Thus, as has been pointed out in the prior art, such devices may be used both ways. The present device, however, has deliberately been designed, by use of abutment surface 26, to avoid the possibility of inadvertent tightening of a cap already tight, in the hands of careless or inexperienced users, with possible damage to cap, container and its contents. Such a construction is especially valuable in view of the fact that directional teeth 5 will harrnlessly slip if the device is inadvertently turned in the wrong direction, thus giving warning to the most inexperienced user that he is'turning the wrong way.

In addition to the advantages noted above, the large, flat overhead abutment surface encourages proper use, especially with the large majority of caps having flat tops. By holding the flat top against the fiat abutment surface 26, improper tilting and consequent poor engagement of the jaws are avoided.

In summary, the provision of abutment surface 26 cooperates with the'limited height of the jaws to avoid engaging the curled ring 30 on the caps; it makes inversion of the device fruitless, thus preventing tightening when loosening is intended and avoiding damage to cap, container and contents; it maintains the proper directionalcharacteristics of the teeth so that there is harmless slipping and warning to the user when the device is turned in the wrong direction; by providing a large, flat overhead surface for abutment with the fiat tops of screw caps, it encourages proper manipulation and avoidance of tilting and poor gripping; and as already shown, it lends itself to the provision of a multiplicity of ports near each jaw to provide necessary visibility without loss of the structural strength needed to avoid spreading of the jaws.

Seizures 0 Caps Many tests made during the development of the present invention disclosed that when the crotch angle is small enough, caps tend to wedge so tightly between the jaws after the cap is loosened that considerable effort is required to dislodge the cap from the jaws; in fact, so great is the force required that it is frequently necessary to employ a prying tool to free the cap. While freeing of the cap may be achieved otherwise, involving certain manipulations of the device, a degree of skill is required of the user, deemed detrimental to the value of the device, especially in view of the fact that the present invention avoids this problem completely by means of a solution which will be explained in the section headed Angle of Crotch.

Coating of the Smooth Leading Jaw It was further found that the presence of a coating of certain substances on the leading jaw surface aifected the seizures of caps, such explaining the erratic results of many hundreds of tests which had to be discarded. In testing the effects of varying the crotch angle on the incidence of seizures, it was soon apparent that the seizures increased as the crotch angles were made smaller, as will be fully shown in the section headed Angle of Crotch. The erratic results mentioned led to confusion until the discovery was made that thin coatings of sticky, gummy materials in barely perceptible quantities had the effect of not only enormously increasing the incidence of seizures, but often requiring inordinately strong effort to free the caps. Hundreds of earlier tests were repeated because it was realized that absolute cleanliness of the leading jaw had not been maintained in the tests and that such cleanliness would not be maintained in practice.

Under actual conditions, the contents of containers often tend to reach the exteriors of' the caps, especially when re-used frequently, and it is difiicult to keep the same clean. The various substances reach the exteriors of the caps and are then applied to the surface of the leading jaw, such discovery being difficult to find, in View of the slight coatings often involved.

The tests mentioned were later made on substances such as paints, varnishes, shellacs, lacquers, honey, jams, sugary beverages, sticky and gummy food substances, others which become gummy on drying, glue, etc. Each test was then repeated with a scrupulously clean leading jaw surface. Each of these substances, in thin and thick coatings, causes profound increases in the incidence of seizures of caps, with heavily disproportionate forces required to dislodge the caps from the grip of the jaws. Another effect noted was that even some of the paints used on certain caps create a similar problem.

In some past devices, the entire surface was painted or lacquered, the latter coating being the worst possible coating as shown by the tests mentioned.

Efiect of Dalling of the Teeth In making the experiments which will be described presently, it was necessary to introduce another influential variable. It will be recalled that a series of tests was made with a view to determining the etfect'of various tooth forms, locations, etc. In this connection, tests were made with blunted teeth, as described in the section headed General Construction Requirements. So pronounced were the effects of even the slightest blunting of the teeth, and in view of the inevitability of wear and dulling of the teeth with time, it was decided to duplicate all tests with teeth dulled to simulate wear.

As the tests, which will be described in the sections headed Angle of Crotch and Pitch of Teeth, will show, the effects of dull teeth are so marked as to make the prior devices ineffective whereas the present arrangement avoids the defects thereof.

Angle of Crotch The prior art shows wide confusion regarding the angle of crotch to be used in devices of the type shown herein. In the development of the present invention, it became evident that the prior art could not be relied upon for assistance in the choice of a proper crotch angle. To confirm certain concepts in the present invention, a long series of tests was made with a view to determining the effects of using various crotch angles, on such vital matters as seizures fully described above in the section headed Seizures of Caps; the production of dangerous burrs capable of cutting the hands of the user when the cap is re-used; and the incidence of slippage due to poor gripping of the cap, often resulting in the production of burrs as well as in complete failure to unscrew the cap.

The conditions of the tests were as follows:

1) Tests were made with the teeth sharp and with the leading jaw surface quite clean.

(2) The tests were repeated with the teeth still sharp but with the smooth surface of the leading jaw coated as described in the section headed Coating of the Smooth Leading Jaw.

(3) All tests were repeated with the leading jaw surface quite clean, but with the teeth dulled to simulate wear, as described in the section headed Effect of Dulling of the Teeth.

(4) All tests were duplicated with both knurled and plain caps.

(5) Both new and worn caps were separately tested.

Finally, it may be stated that a large range of cap sizes was tested; all caps were tightened as much as was safe with the container used; no crotch pressure of the type explained in the section headed Crotch Pressure was permitted; all tests were made with identical types of jaws, form and pitch of teeth, height of jaws, etc.; and at least one device of the preferred embodiment was always used as a control.

The significant results of these tests were carefully plotted and they are reproduced in FIGS. 32, 33 and 34.

FIG. 32 is concerned with the effects of varying the angle of crotch on the incidence and frequency of seizures. As shown by the solid curve 38, even when the teeth are quite sharp and the leading jaw is quite clean, intolerable seizures occur at all angles under 30. Even a 27 /2 angle seizes of the caps tested, while a angle seizes 90% of the caps. In view of these disclosures, it is remarkable to note the large number of devices in the prior art which show crotch angles which are far smaller than those noted above.

The profound effects of applying a coating to the smooth surface of the leading jaw are shown in the dotted curve 39. Here a thin, sugary coating had been permitted to dry on the leading jaw. The 27- /2 angle which had seized only 10% of the caps tested before the coating was applied now seized 90% of the caps. The 30 angle which was previously free of all seizures now jumped to fully 100% of the caps tested. Similarly, the 32 /2 angle shows seizures of 30% of the caps tested, and it was free of seizures before the coating was applied.

Even with the leading jaw coated as described, an angle of 35 for the crotch is entirely free of seizures, and the behavior of curve 39 (FIG. 32) indicates that nothing under 33 would be safe. It is understood, of

course,'that all the other preferred elements of the present invention were used in these tests.

. At this point it is worthwhile to note that caps on glass containers are often heavily stuck due to the drying of glue, lacquers and the like on the threads. With crotch angles which were substantially lower than 35, there was a definite tendency to break the glass container in such cases, evidently due to the greater wedging pressure at such smaller angles. In such cases, cap, container and contents are usually lost and the danger to the users hands is appreciable. In view of the foregoing, there is added good reason for rejection of the small angles frequently encountered in the prior art, many of which are as low as 10 or 15".

The influence of varying the angle of crotch on the production of dangerous burrs is shown on solid curve 40 of FIG. 33 with teeth sharp and leading jaw clean. It is clear that, under these conditions, only when the crotch angle is quite large, that is, 45 or over, is there production of dangerous burrs. At that angle, 8% of the caps tested showed burrs. The production of any dangerous burrs whatsoever cannot be tolerated despite the very low percentage of caps affected. Accordingly, 45 angles or larger are unacceptable.

The influence of varying the angle of crotch on the incidence of slippage, often severe enough to result in complete failure to unscrew the caps and frequently accompanied by the production of dangerous burrs, is shown in FIG. 34. The solid curve 41 shows that even with sharp teeth and with the smooth leading jaw surface quite clean, at a 40 crotch angle, there is unacceptable slippage shown by 10% of the caps tested, and at 45 the failure jumps so 30% of the caps tested. Therefore, both angles must be rejected, especially since the tests included complete failure to unscrew the caps.

Even worse is the showing made by the larger angles when the teeth are dulled, as shown in the broken curve 42. With teeth dulled and with the leading jaw surface quite clean, all tests at 40 and over completely failed to unscrew the caps. The behavior of the curve indicates danger at any angle over 38.

It is of the essence, however, to note that the 35 angle of crotch is free of slippage and that even with very heavy crotch pressure, the larger angles failed.

Summarizing the results of the tests shown in the graphs described above, it should be clear that the preferred crotch angle is 35 or within a reasonable range thereof. It is the smallest angle which is safely free of seizures and the largest angle safely free of slippage. It is also free of burr production. It performs perfectly at negligibly low crotch pressure.

Crotch Pressure Crotch pressure has been referred to above in several places and further explanation is justified at this point. Due to the automatic wedging action which results from the application of unscrewing torque, as previously described in the section headed OperationSchematic Form, the user need not consciously apply any crotchward force on the cap. He merely slides the cap relatively into contact with both jaws simultaneously and starts to turn. This is a decided advantage over devices in the art in which, due to the use of too large a crotch angle, or the use of teeth of improper form, pitch, location ororientation, great crotch pressure must be applied by the user toavoid slippage and failure to unscrew the cap, with the danger of burr production.

The burden of being required to exert strong crotch pressure in such prior art devices is not the only disadvantage entailed. Possibly even more serious is the fact that Because of the above factors, it should be evident that avoidance of the need for crotch pressure is an important aspect of this invention. The present invention devices require no conscious application of crotch pressure once the cap is placed lightly into contact with both jaws simultaneously. Accordingly, no crotch pressure was permitted in the tests.

Pitch of the Teeth The tests which follow were conducted under the same rigid conditions detailed above in the section headed Angle of Crotch, with the exception that in the present tests the crotch angle is held constant at 35 and the pitch of teeth varied. The results are shown in the graphs of FIGS. 35, 36 and 37. Pitches varying from 16 through 48 teeth per inch are shown, although many more were tested, and only the most significant results are shown.

The solid curve 43 of FIG. 35 shows that there was no effect on seizures when the pitch of the teeth was varied.

Solid curve 44 in FIG. 36 shows that with the teeth sharp and with the leading jaw surface clean, dangerous burrs are produced when the teeth are relatively coarse. Thus, at 16 teeth per inch, dangerous burrs are produced on 100% of the caps tested, and any pitch under 32 teeth per inch produces dangerous burrs on at least some of the caps tested. It is undesirable to have any burrs at all. Broken curve 45 shows that after the teeth become dulled, the occurrence of burrs at a pitch of 24 teeth per inch jumps to 30% of all caps tested and that some burrs occur even at 32 teeth per inch pitch, a pitch generally regarded as quite fine.

A pitch of 38 teeth did not produce burrs even when the teeth were dull.

Reference to solid curve 46 in FIG. 37 shows that varying the pitch of the teeth, per se, had no significant effect on the incidence of slippage, so long as the teeth were quite sharp.

Broken curve 47 shows that when the teeth become dull, slippage is heavy with coarse teeth, there being slippage on 50% of the caps tested with 24 teeth per inch pitch which is not ordinarily regarded as being coarse. There is some slippage at 32 teeth pitch and zero slippage at 38 teeth per inch, but at 48 teeth'per inch there was complete failure to unscrew the caps. Atthe extremely fine pitches greater than 38 teeth per inch, there was a tendency of the teeth to load up with paint off the cap, and complete slippage and failure occurred. At 38 teeth per inch or less, the paint fragments did not tend to load the teeth sufiiciently to cause slippage.

At 38 teeth per inch pitch there was no slippage, even with dulled teeth. This pitch is also the preferable pitch with respect to burr production.

Microscopic examination of the caps used in the above tests led inevitably to the selection of the preferred pitch range, finer by far than had customarily been used in the art. Among other observations, it was noted that with the preferred fine pitch, four or five teeth invariably left their impression on very tight caps after loosening. On the other hand, with the coarse teeth commonly used in the art, it was noted that there was an impression of only one or two teeth. Frequently it was seen that the friction had'pro'ved inadequate and a shiny streak along the cap periphery, together with asharp burr curled up at the end of the streak, testified to the slippage. It was also noted that with serrated caps, a coarse tooth slips easily off the top of a serration, causing a burr; whereas with the preferred fine pitch, several teeth engage simultaneously to prevent such slippage.

Omission f Gaps It was mentioned above that both jaws subtend directly from abutment surface 26 and that there was no gap whatsoever between the abutment surface and the gripping surfaces of the jaws, when referring to FIGS. 2, 6 and 13. Specifically, this means that the teeth of trail- 14 ing jaw 4 directly adjoin overhead abutment surface 26 and that the smooth gripping surface 3 of leading jaw 4 also directly adjoins overhead abutment surface 26. It is within the scope of the present invention to leave a gap between the tops of these gripping elements of the jaws and the abutment surface 26, as is commonly done in the art. Such a construction is shown in sectional fragmentary FIG. 17. A toothed trailing jaw 48 is spaced away from a body member 50 so that there is a substantial gap 51 between top 49 of the teeth and body member 50. Likewise, there is a gap 54 between the top 53 of the smooth leading jaw gripping surface 52 and body member 50.

A large number of tests were made which showed that devices with such gaps, whether above the teeth of the trailing jaw or above the smooth gripping surface of the leading jaw, are inferior in scope and performance and should be avoided. As an example of the limitations in scope, when caps having thin, flanged heads of the type shown in FIG. 26 are used in connection with the gapped jaws of FIG. 17, it is not easy to make proper engagement; the thin, flanged head of the cap often enters into one or both of the recesses at gaps 51 and 54. Proper manipulation obviously demands care and skill. Comparison should be made with FIG. 26 showing a cap of the same type in position to be unscrewed on the present device, illustrating the relative ease of manipulation.

A great many tests were made, as above mentioned, using various heights of gaps. A complete series shown in the graphs of FIGS. 38, 39 and 40 show the effect of various heights of gaps above the teeth of the trailing jaw only. FIGS. 41, 42 and 43 show the effects of using various heights of gaps above the gripping surface of the smooth leading jaw only. All tests were made under the severe conditions detailed in the section headed Angle of Crotch, except that in the present tests the crotch angle was held constant at 35, while the gaps were varied. In all the tests, in addition to testing gaps varying from of an inch up, the preferred no-gap construction of the present invention was also tested as a check and control. The total height of the jaws was held in all cases to a very safe height of of an inch from the abutment surface to the bottom of the gripping elements. Thus, as described in the section headed Height of Jaws, the height was safely small enough to avoid gripping the curled ring 30 of the caps. Obviously, as the gap was increased, the net height of the gripping element was decreased, as shown in the charts.

Without attempting a complete analysis of each of the curves shown in FIGS. 38 through 43, certain broad conclusions can be reached:

(1) Only when there is no gap whatsoever above either the teeth 5 of the toothed trailing jaw 4 or above the smooth gripping surface 3 of the leading jaw 2 is perfect performance obtained, with no seizure, burr or slippage, as shown in all the curves of the figures at the No Gap (or zero) graduation on the X axis of the graphs. It is to be understood that the term No Gap includes insig nificant gaps, e.g., a few thousandths of an inch up to of an inch.

(2) The behavior of the solid curves 55 through 60 shows that if the teeth were always sharp and the smooth leading jaw could always be kept meticulously clean, the presence of gaps would not interfere with perfect performance with only one exception, the .156 inch gap on curve 55.

(3) As explained in the section headed Coating of the Smooth Leading J aw, a coating is regarded as being inevitable under practical conditions of use. The dotted curves 61 and. 62 show that .once there is such a coating on the leading jaw surface, the incidence of seizures increases with amazing steepness as the gap increases in height. Only the tiniest gaps are safe for seizures, but even these are not to be relied upon, as will be shown below. 7 i

(4) The incidence of dangerous burrs, as shown in Alternative Form Used for Tightening Caps As an alternative construction to that seen, for example, in FIGS. 1 and 2, if instead of securing the toothed strip 12 to inside surface 11 of jaw 4, the toothed strip is secured to inside surface 3 of jaw 2, the teeth remaining oriented as previously described, that is, with their steep front cutting faces 6 facing toward the apex of the crotch, then the device can be used only for tightening screw caps on their containers. The toothed jaw would still properly be designated the trailing jaw, since it would now trail when the device is rotated clockwise (plan view) for tightening caps. The same advantages which apply to the preferred embodiment also apply here.

Combination F arms The screw cap removing devices described above preferably have unusually large body portions 10 of unusually extended length, to enable handling a large range of cap sizes. These and other characteristics are highly valuable in that they enable unusual advantages for combining with a plurality of other opener members by providing uniquely substantial body supports and exceptionally great leverage for facilitating the opening of a large variety of container closures as well as for the piercing of liquid-containing cans.

Crown Cap Remover FIG. 1 shows a cutout portion 76 having a beveled lip 77 for the removal of crown or crimped caps in a well known manner. Similar cutout portions are shown in FIG. 4. Fragmentary FIG. 18 shows the preferred manner of use, with the device of FIG. 4 inverted and ready for the removal of a crown cap 78 from a beverage bottle 79. The substantial length of the entire device, in each case, provides exceptionally good leverage for easy operation of the crown cap remover. In FIG. 1, the friction cap remover is provided without any increase in cost of manufacture, and structural strength is undisturbed despite the large cutout required. In FIG. 4, the large blank that is required anyway for body portion 10 and the other opener members to be described below provide ample metal for cutout 76 without sacrifice of necessary structural strength.

Can Piercer Located safely remote from the users hands, at the extreme forward end of the device of FIG. 4 is a canpiercing blade 81 and a bead-engaging lip 82. These are shown ready for the piercing of a beverage can 80, in fragmentary FIG. 19. Blade 81 is unusually large in size so that piercing of one opening will serve adequately, rather than the two that are ordinarily required to assure smooth pouring. In spite of the added burden of piercing a substantially larger opening, the unusually great leverage available makes this operation easy. The parts are arranged to compel inverted operation of the device. Thus, when lifting upward, the user feels only the smooth, rounded corners of the bent metal at the sides, rather than the sharp sheared edges which would be pressed against if there were upright operation.

Pry-Type Lid LiftersScrewdriver Positioned slightly rearwardly of blade 81 is a pair of pry members '83 having beveled edges 84 to facilitate insertion under various types of lids and caps such as, for example, the friction cover 85 of a paint can 86 which is shown in FIG. 20 with the cover about to be pried loose from the can. Pry members 83 do not project outward at right angles to the longitudinal axis of the device, but rather at an angle bent toward blade 81. The purpose of this arrangement will be clear from inspection of FIG. 20. No matter how large the diameter of can 86 may be, the upper shoulder of body portion 10 cannot crowd into contact with can 86 and interfere with the proper prying action.

Often such can covers are heavily stuck, and the unusually great leverage provided in the present device makes removal very easy.

As shown in fragmentary FIG. 21, pry members 83 are useful for the removal of large friction-type caps from jars 88. Beveled edge 84 of pry members 83 is inserted in a groove 90 formed between a bead 89 on jar 88 and a flange 91 on cap 87, and by a slight rocking or twisting of the device reacting between the bead and flange, cap 87 is readily lifted. FIG. 22 shows a similar use with certain types of bottles 92 having friction caps 93. The opening operation is similar to that described for FIG. 21. FIG. 23 shows a somewhat different use for member 83, namely, its use as a screwdriver in certain types of threaded closures. A cap 94 is slotted as at 95 for the reception of a large screwdriver blade so that threaded member 96 may be turned relative to a threaded container 97. This construction is found on certain types of metal flasks, oil reservoirs and the like.

In the drawings, both members 83 are shown as duplicate structures. It is within the scope of the present invention to make one of the shape shown and most suitable for prying purposes, and the other could be formed in the shape of a conventional screwdriver, that is, with a narrow, thicker blade of the usual conformation.

In the operation of the pry member just described, unusually good leverage is of great value in facilitating easy operation.

Hook Lifters for T umbler-Type Caps, Etc.

Straddling the cutout 76 in FIG. 4 is a pair of bentdown arms 98 which are provided at their extremities with lifter hooks 99. Such hooks are not unknown in the art, but these are quite unusual in the following respects: The hooks are spaced apart an unusually large distance; the bent arms depend a greater distance than is usual; the shape and depth of throat of the hooks are also unusual in the art. The reason for these unusual characteristics is shown in FIG. 24 which depicts the device ready to be lifted to cause the removal of a friction-type cap which is secured to a tumbler 101. Such so-called tumble-type containers are known to be especially troublesome in removal of the cap. There is no bead on the tumbler against which a pry tool could react, so a hook-type lifter is used for the purpose. Reaction isagainst the top of cap 100. Thus, in FIG. 24, when the handle is lifted upwardly, there is a reacting force pressing against cap 100 at the point designated 102. There is, therefore, a conflict of forces against the cap, tending to bend the thin metal out of shape as hooks 99 lift the edge of the cap upward while the cap is pressed downward'at point 102. In ordinary hook lifters, the caps are often distorted so badly as to disable re-use, and efforts to bend them back into shape are usually fruitless.

' As mentioned above, lifter hooks 99 are spaced apart by a distance far greater than is usual in the art, thus engaging the cap 100 at tWo points far apart on its periphery. This fact, together with the fact that the device is provided with a very broad, rounded bearing surface at point 102, also unusual in therart, distributes the stresses over a wider area of the cap and the danger of harmful distortion is substantially reduced. The broad bearing surface mentioned is nicely provided cooperatively by the exceptionally large can-piercing blade 81, previously described. The unusually wide spacing of the hooks fits nicely into the requirement for wide cutout 76, previously described,

1'? and the unusually long body and handle extension combine to provide extraordinarily good leverage. In this manner, the devices are mutually dependent and cooperatively combined.

Another type of troublesome friction-held cap 103 is illustrated in fragmentary sectional FIG. 25. The container 104 has an upper frusto-conical seat 105 into which the tapered cap 103 is pressed. The cap has a slightly bent flange 106 which acts as a stop to limit the depth of insertion of the cap in the seat. This construction positions the flat top 107 of the cap at a level substantially below flange 106. Because of this sunken-deck construction, such devices are unusually diflicult to open, and openers in the art often fail for the reason that the handle must be swung upward so high that the usual hooks slip out of engagement. In the present device, due to the shape and depth of throat on the hooks 99, as well as the other unusual spacings and widths mentioned, there is no difiiculty in loosening such caps.

It should be apparent that variations in construction can be made it the foregoing details without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

1. In a device for gripping and turning screw caps of threaded containers, the combination including a body member having a leading jaw and a trailing jaw mutually disposed to form a crotch defining an angle between 33 and 38 degrees, a smooth cap-gripping surface on said leading jaw, sharp file-like cap-gripping teeth inclined toward the narrow end of said crotch on said trailing jaw, and a flat portion on said body member above and between said jaws and providing a fiat overhead abutment surface for screw caps.

2. In a device for engaging and rotating screw caps of threaded containers, the combination including a rigid body member having a leading jaw and a trailing jaw disposed in angular relationship with each other and forming a crotch-shaped cap-engaging socket, a smooth capengaging surface on said leading jaw, sharp directional cutting-type teeth on said trailing jaw, the relatively steep faces of said teeth being oriented toward the extended apex of said crotch, the pitch of said teeth being between 33 and 47 teeth per inch, and a flat overhead abutment surface for screw caps.

3. In a device for engaging and rotating screw caps of threaded containers, the combinations including a body member having a leading jaw and a trailing jaw disposed in angular relationship with each other so as to form a cap-engaging crotch, said crotch defining an angle between 33 and 38 degrees, a smooth cap-engaging surface on said leading jaw, sharp inclined cutting teeth on said trailing jaw, the steep faces of which face toward the narrow end of said crotch, said teeth having a pitch between 33 and 47 teeth per inch, and an overhead abutment surface adapted for abutment by screw caps during operation.

4. The device of claim 1 wherein the teeth are positioned in contact with said overhead abutment surface without leaving a gap therebetween.

5. The device of claim 3 wherein the effective height of the cap gripping elements of the jaws is between and of an inch, said teeth being positioned in contact with said overhead abutment surface without leaving a gap therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 1,620,891 Irvine Mar. 15, 1927 1,707,804 Haase Apr. 2, 1929 2,046,334 Loeber July 7, 1936 2,053,246 Lurcott Sept. 1, 1936 2,810,311 Smith Oct. 22, 1957 FOREIGN PATENTS 614,982 Great Britain Dec. 30, 1948 772,929 Great Britain Apr. 17, 1957 

1. IN A DEVICE FOR GRIPPING AND TURNING SCREW CAPS OF THREADED CONTAINERS, THE COMBINATION INCLUDING A BODY MEMBER HAVING A LEADING JAW AND A TRAILING JAW MUTUALLY DISPOSED TO FORM A CROTCH DEFINING AN ANGLE BETWEEN 33 AND 38 DEGREES, A SMOOTH CAP-GRIPPING SURFACE ON SAID LEADING JAW, SHARP FILE-LIKE CAP-GRIPPING TEETH INCLINED TOWARD THE NARROW END OF SAID CROTCH ON SAID TRAILING JAW, AND A FLAT PORTION ON SAID BODY MEMBER ABOVE AND BE- 